Improved indoor lighting improved healthy aging at home - an intervention study in 77-year-old Norwegians

Introduction: Healthy aging and good quality of life is important to allow older people to live at home. Lighting is a significant environmental attribute promoting visual, physical, and mental health. Due to normal visual age changes, older people need more light, but improving indoor lighting levels receives little attention. Objective: To investigate the impact of improved home lighting on abilities to perform activities of daily living (ADLs) and quality of life in healthy older people. Methods: Sixty healthy 77 years old living at home participated during the 4-month dark winter period. In the intervention group (IG, n=30), the living room lighting was optimized by providing lamps and a basic control system with three preset levels (normal, medium, low). Participants chose the light level and kept a diary. No change was implemented for the control group (CG, n=30). A questionnaire measured self-reported visual and general health and ability to perform ADL in regards to lighting before and after the intervention in both groups. Results: In the IG, lighting levels significantly improved self-assessed lighting levels, abilities to perform ADLs, and read and write in the living room (all p<0.03). In the CG the only change was a deterioration in performing ADLs ( p<0.05). The difference in change was significant between the IG and CG (all p<0.02). "Normal" lighting was the preferred level and increased comfort and well-being. The IG also resumed visually demanding tasks, and acknowledged that avoiding these tasks were mainly due to poor lighting. Conclusions: Good vision is essential in promoting healthy aging at home and require adequate lighting. This can easily be achieved using a basic light system. Adopting to higher lighting levels evolves quickly. Our results suggest that improved quality of light could improve quality of life, and lighting should be included as a factor promoting healthy aging at home.